Help aging my chickens and gender on the littlest if possible

[BizzyB]

Rhode Island Red, Dominque, Black Giant, and Easter Egger. RiR and Dominque were bought together and the Black Giant and Easter Egger were bought together. Trying to see if youngest two are past brooder age as I think they may be or still need a bit

 

[JedJackson]

So far I see no males, but the little ones are still a bit young. I think they are 3 to 4 weeks old, and the older ones are 7-8 weeks old.

 

[Pigeony]

Look to be all pullets, little ones are still young enough to prove me wrong though